This is a continuation-in-part of Ser. No. 09/720,021 filed Dec. 19, 2000 which is a xc2xa7371 of PCT/US00/10680 filed Apr. 19, 2000 which claims benefit of Ser. No. 60/130,054 filed Apr. 19, 1989.
The present invention relates to rotary cutting tools and, more specifically, to rotary cutting tools with inserted cutters placed about the axis of rotation.
Rotary cutting tools are used in a wide range of manufacturing applications to machine a wide variety of materials.
One of the existing problems with rotary cutting tools with inserted cutters has been the ability to maximize the number of inserted cutters in the periphery or face of the rotary cutting tools. The prior art has used a variety of mechanical locking mechanisms to attach the inserted cutter to the rotary cutting tool body. These mechanical attachment mechanisms are often located in the plane of the rotation of the inserted cutter. The inserted cutter attachment mechanism thus reduces the amount of cutter body available for inserted cutters limiting the number of inserted cutters that may be attached. One such mechanism is shown in U.S. Pat. No. 4,275,853 to Kruez, et al. Another is shown in U.S. Pat. No. 5,725,416 to Russell.
Other attachment mechanisms are shown in U.S. Pat. Nos. 2,079,995 to Hodgkins and 4,522,538 to Lindsay. In each of these devices the locking element engages both the insert and the side of the tool body. This arrangement inhibits the ability of the locking element to precisely locate the insert.
Another problem with rotary cutting tools with inserted cutters is associated with the brazing of inserted cutters to the face or periphery of the cutting tool body. When inserted cutters are brazed to the cutting tool body, the precise geometry of the cutting surface must be machined after brazing attachment, increasing cost of manufacture. Also resharpening or replacing brazed inserted cutters in the periphery or face of the rotary cutting tool increases the costs of manufacture of the cutting tool. Additionally, complex shapes and geometries are difficult or impossible to machine in the brazed inserted cutter after attachment to the cutter body.
According to the present invention, there is provided a cutting tool comprising a tool body having at least one slot therein. The tool body also defines a groove. The cutting tool further includes a cutting tool insert disposed in the slot. The cutting tool insert has a body portion defining at least one side edge. The side edge defines an outermost edge surface and a geometrical configuration. The cutting tool insert further includes a cutting portion. The cutting tool further includes at least one attachment ring having an inner area and an outer area fixed relative to the tool body. The inner area of the attachment ring is axially spaced from the tool body. The attachment ring applies a holding force only to the side edge of the body portion of the cutting insert and the groove on the tool body to retain the cutting insert in the slot.
One feature of the present invention provides a rotary cutting tool with inserted cutters placed about the axis of rotation. These inserted cutters may be placed on the periphery, face, or a combination of surfaces about the rotational axis of the cutting tool body.
Another feature of the present invention provides a rotary cutting tool with inserted cutters held in position by a mechanism that lies about the rotational axis of the tool. The attachment mechanisms position the inserted cutters precisely about the rotary tool body through use of related or complimentary geometry formed in the inserted cutter and attachment mechanisms. The related geometries hold the insert in location without reducing the available circumference of the cutting tool body thus increasing the amount of inserted cutters that can be attached to a given circumference.
Another feature of the present invention provides the attachment mechanisms, inserted cutters and their related geometries may be used to position and attach the inserted cutters to the rotary cutting tool body. The related geometries of the attachment mechanisms and the inserted cutters are manufactured identical to each other to provide a precise fit and secure attachment to the rotary cutting tool body.
Another feature of the present invention provides the attachment mechanisms, inserted cutters and their related geometries may be used to position and attach the inserted cutters to the rotary cutting tool body. The related geometries of the attachment mechanism and the inserted cutters are manufactured to create interference between the attachment mechanism and the inserted cutters to provide a precise fit and secure attachment to the rotary cutting tool body.
Another feature of the present invention provides the attachment mechanisms, inserted cutters and their related geometries may be used to position the inserted cutters as a temporary fixture to braze the inserted cutters precisely in position relative to the cutter body. The use of the attachment mechanism, inserted cutters and their related geometries allows the attachment of the inserted cutters precisely without the need of machining geometries of the cutting surface after brazing attachment, reducing the cost of manufacture.
Another object of the present invention is to provide an attachment ring that only engages the tool body in the groove and is otherwise spaced from the tool body along the axis of rotation of the tool body. The attachment ring includes a geometrical configuration that engages the groove having a complimentary geometrical configuration on the tool body and a complimentary geometrical configuration on the side edge of the insert. Otherwise the attachment ring does not engage the insert. In this manner, the precise orientation of the insert member can be achieved by providing an interference fit between the attachment ring and the insert member.
Another object of the present invention is to provide an attachment ring that is made of a relatively softer material than the insert. With this arrangement, when the attachment ring is secured to the tool body, and the attachment ring contacts the insert, the side surface of the insert is embedded slightly into the relatively softer ring. This helps maintain the insert in an appropriate orientation.